<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    {% macro input(name,type="text") %}
        <input type="{{type}}" name="{{name}}" class="form-control" required placeholder="请输入{{name}}"/>
    {% endmacro %}
    <form>
        {{ input("username") }}
        {{ input("email",type="email") }}
        {{ input("password",type="password") }}
        current_year: {{current_year}}

        {% set active_page = 'macro' %}
        active_page:{{active_page}}
        active_page:{{active_page+active_page}}

        {% with age = 100 %}
        {{age}}
        {% endwith %}
        {{age}}
    </form>
</body>
</html>